Zonisamide is metabolized by the liver and eliminated by the kidneys;
caution should therefore be exercised when administering Zonisamide to
patients with hepatic and renal dysfunction
Kidney Stones:

Patients treated during the development of Zonisamide, 40 patients (4.0%)
with epilepsy receiving Zonisamide developed clinically possible or
confirmed kidney stones

The analyzed stones were composed of calcium or urate salts. In general,
increasing fluid intake and urine output can help reduce the risk of stone
formation, particularly in those with predisposing risk factors. It is
unknown, however, whether these measures will reduce the risk of stone
formation in patients treated with Zonisamide. Zonisamide was associated
with a statistically significant 8% mean increase from baseline of serum
creatinine and blood urea nitrogen (BUN) compared to essentially no change
in the placebo patients. The increase appeared to persist over time but was
not progressive; this has been interpreted as an effect on glomerular
filtration rate (GFR)Patients should be advised as follows:Zonisamide may
produce drowsiness, especially at higher doses. Patients should be advised
not to drive a car or operate other complex machinery until they have gained
experience on Zonisamide sufficient to determine whether it affects their
performance.

Patients should contact their physician immediately if a skin rash develops
or seizures worsen.

Patients should contact their physician immediately if they develop signs or
symptoms, such as sudden back pain, abdominal pain, and/or blood in the
urine, that could indicate a kidney stone. Increasing fluid intake and urine
output may reduce the risk of stone formation, particularly in those with
predisposing risk factors for stones.

Patients should contact their physician immediately if a child has been
taking Zonisamide and is not sweating as usual with or without a fever.

Because Zonisamide can cause hematological complications, patients should
contact their physician immediately if they develop a fever, sore throat,
oral ulcers, or easy bruising.